Currently, popular memories include the static random-access memory (SRAM) and the dynamic random-access memory (DRAM). The advantage of the former is its fast speed while the advantage of the latter is its high density. Nonetheless, these two types of memories are mainly formed by transistors, which feature large sizes, compromising advantages, and volatility. Advanced memories mainly control the magnetism of materials to produce 0 and 1 states. They can be made of nonvolatile memory materials and own the merits of high speed and small size.
Spintronics devices are developing prosperously. In the past, magnetic moments are arranged on a plane and used as the sensing mechanism. Unfortunately, to produce significant flipping in magnetic vectors, the adopted materials should have a certain thickness, making them inappropriate for mass production. Electron spins mean that the angular momenta of electrons behave classically and act on electron orbits along with torques.
To make the magnetic memory devices according to the prior state of art with significant magnetization due to normal orientation of magnetic moments along the plane of materials, the thickness of magnetic materials should be increased, and two materials should be assembled by attachment. Nonetheless, this method increases the volume of memories, disfavoring mass production.